The present invention relates to methods and devices which make it possible simultaneously to connect several pairs of ends of assemblages of textile threads, the threads of these assemblages being multifilaments.
By way of example, an assemblage of threads is referred to as a "twist" when it is formed of several threads combined by a single twisting operation.
Such assemblages are used, for instance, to reinforce plastic and/or rubber articles, such articles being, for instance, belts, hoses and tires.
The invention, in particular, relates to methods and devices which make it possible to connect two twists by joining the two pairs of ends of threads of these twists.
The conventional methods of joining textile assemblages are essentially of two types:
The first type consists of mechanical joinings using various methods, such as the making of knots or splices; PA1 These methods have the drawback of causing an increase in the diameter of the region where the joinder has been effected; they also give rise to free ends; these two consequences are disadvantageous upon the subsequent use of these assemblages, for instance in automobile tires; PA1 The second type consists of air entanglement techniques, currently referred to by the expression "air splicing"; these techniques give excellent results on multifilaments which are without twist; on the other hand, it is difficult to obtain a joinder of good quality on twists, since the threads of these twists are multifilaments which have been subjected to a twist. PA1 (a) The ends of the assemblages are subjected to an untwisting operation in order to separate the threads of these ends from each other so as in this way to obtain free thread ends; PA1 (b) As many junction pairs are formed as there are threads in each of the assemblages, each pair comprising a free end of one thread of each assemblage; PA1 (c) The filaments are untwisted in at least a part of each of the threads, in the junction pairs; PA1 (d) The untwisted parts are placed side by side in each junction pair so as to obtain a junction region, the junction regions being offset axially with respect to each other; PA1 (e) The filaments of the two threads in each of these junction regions are assembled together by air splicing; PA1 (f) All the threads which have thus been combined are assembled together by twisting in the direction of twist of the assemblages. PA1 (a) So-called separation means which make it possible to subject the ends of the assemblages to an untwisting operation so as to separate the threads of these ends from each other in order in this way to obtain free thread ends; PA1 (b) So-called pairing means, making it possible to form as many junction pairs as there are threads in each of the assemblages, each pair having a free end of one thread of each assemblage; PA1 (c) So-called untwisting means making it possible to untwist the filaments in at least a part of each of the threads in the junction pairs; PA1 (d) So-called placement means, making it possible to place the untwisted parts side by side in each junction pair so as to obtain a junction region, these means being so arranged that the junction regions are offset axially from each other; PA1 (e) Air splicing means making it possible to assemble the filaments of the two threads with each other in each of these junction regions; PA1 (f) So-called assemblage means making it possible to assemble all the threads which have thus been combined, by twisting them together in the direction of the twist of the assemblages.
The object of the invention is to overcome these drawbacks.